Cooling means for hydrodynamic torque converters



Jan. 18, 1955 K. e. AHLEN 2,699,642

000mm MEANS FOR HYDRODYNAMIC TORQUE CONVERTERS Filed May 10, 1949 2' Sheets-Sheet l W l i iii, I

' OINVENTOR Jan. 18, 1955 K. c5. AHLEN 2,699,642

COOLING MEANS FOR HYDRODYNAMIC TORQUE CONVERTERS 2 Sheets-Sheet 2 Filed May 10, 1949 D INVENTOR Kczr/ 5 14/2] 81 2 United States Patent COOLING MEANS FOR HYDRODYNAMIC TORQUE CONVERTERS Karl G. Khln, Stockholm, Sweden, assignor, by mesne assignments, to Jarvis C. Marble, New York, N. Y., Leslie M. Merrill, Westfield, N. L, and Percy H. Batten, Racine, Wis., as trustees Application May 10, 1949, Serial No. 92,399 2 Claims. or. 60-12) The present invention relates to the cooling of hydraulic torque converters and more particularly to the cooling of such converters of the hydrodynamic type in which pump and turbine members operate in a working chamber providing for the circulation of working liquid in a closed path of flow, and of which the kind disclosed in Lysholm U. S. Patent No. 1,900,118, is a typical example.

Converters of the character under consideration operate at variable efliciencies, all materially less than 100% efficiency, and the power represented by the diiference between the input power and the output power is transformed into heat which must be dissipated to prevent overheating of the converter.

Heretofore the most common method of cooling converters to dissipate the heat generated has been to withdraw a part of the working liquid from the working circuit, pass it through a separate cooler and return the cooled liquid to the circuit. This arrangement involves certain difliculties and disadvantages among which may be mentioned disturbance to the flow of the working liquid in the working chamber due to the withdrawal and reintroduction of part of the fluid and difliculty in keeping tight and free from leaks the outside separate cooler and the necessary conduits which usually include flexible hose or the like for connecting the cooler with the converter. In connection with this latter difficulty it has to be borne in mind that the working liquid which is ordinarily some kind of oil such as kerosene, diesel oil, or even lubricating oil or various mixtures thereof, is under pressure which may vary from approximately 45 p. s. i., to as much as 90 p. s. i. or even more, when the converter is in operation and also usually has an operating temperature which may and frequently does exceed 212 F., sometimes reaching temperatures of the order of 300 F. Cooling arrangements employing separate coolers for the converter have the further disadvantage of expensive construction and furthermore since the circulation of the liquid is usually effected by taking out liquid from the high pressure zone in the converter for cooling and returning the liquid to a low pressure zone, the circulation of the liquid and cooling of the converter is dependent on the converter being in operation to create the necessary pressure diflerential.

It has further previously been suggested, when converters have been driven by internal combustion engines having liquid cooling systems, to utilize the same liquid as a working liquid in the converter and for cooling the engine, with the engine cooling system and the working circuit of the converter interconnected. Such an arrangement is shown in the aforementioned Lysholm patent. The difiiculty with the latter proposal is that it has been found impractical for numerous reasons to employ the same fluid both for hydraulic working fluid and as engine cooling fluid.

The general object of the present invention is to provide a new and improved means for cooling converters of the kind under consideration, when they are driven by internal combustion engines having liquid cooling systems, which utilizes the engine cooling system for cooling the converter as well as the engine, the cooling of the converter being effected by a surface type heat exchanger between the working liquid and the engine cooling liquid. Other and more detailed objects of the invention and the advantages to be derived from its use will appear as this specification proceeds taken in conjunction with the accompanying drawings forming a part hereof in which;

2,699,642 Patented Jan. 18, 1955 form of converter housing construction embodying the invention;

Fig. 3 is a fragmentary view from above Fig. 2, along line 3-3 and with the outer casing broken away, illustrative of the path of flow of the cooling fluid with respect to the converter casing;

Fig. 4 is a view similar to Fig. 2 of another form of converter casing structure; and

Fig. 5 is a view similar to Fig. 3, along line 55 and with the outer casing broken away, showing the path of flow of the cooling liquid relative to the casing of Fig. 4.

Referring now more particularly to Fig. 1, reference numeral 10 indicates an internal combustion engine to which is secured and from which is driven the hydraulic torque converter, indicated generally at 12 and having a rotationally stationary casing 14 enclosing the working chamber of the converter. So far as the present invention is concerned the construction of the converter may be of well known nature, such for example as that shown in the aforementioned Lysholm patent. The casing 14 is jacketed for cooling liquid, advantageously in a manner to be hereinafter described more in detail. The engine shown is of the liquid cooled type provided with the usual engine cooler or radiator 16 from which the cooling liquid, usually water, is withdrawn through the connec tion 18 by the circulating pump 20 the outlet of which delivers the cooling liquid to the jacket spaces of the engine in the usual manner. The outlet for the cooling liquid from the engine is indicated at 22 and is provided temperature. The outlet 22 is connected with the inlet port 26 of the jacketed converter casing by means of the conduit 28, and cooling liquid leaving the jacketed casing through the outlet port 30 is conducted through conduit 32 to the top inlet connection 34 of the radiator 16. As will be evident from the drawings the engine jacket space and the converter jacket space are in this arrangement connected in series, with the direction of flow of the cooling liquid being indicated by the several arrows 36.

Referring now to Figs. 2 and 3 there is illustrated more in detail a suitable form of jacket arrangement for the converter housing. In this arrangement a portion of the converter housing surrounding the working chamber of the converter is grooved with axially spaced grooves 50 and 52 and an outer shell or jacket 54, which advantageously may be of sheet metal, is secured to the housing (by crimping or equivalent operations for elfecting a fluid tight seal). The jacket 54 provides the inlet and outlet ports 26 and 30 and is also provided with two series of axially extending baflies 56 and 58 arranged to cause zig-zag flow of the cooling liquid around the periphery of the housing from the inlet port to the outlet port, as indicated by the arrows 60. The liquid is forced to flow around the casing by the axially extending partition or wall 62 located peripherally between the inlet 26 and the outlet 30.

Another form of jacket structure for the converter casing is shown in Figs. 4 and 5. In this embodiment the jacket or shell 54 carries axially spaced circumferentially extending baffles 64 and 66 and an axially extending partition 68 for causing the cooling liquid to flow from the inlet 26 to the outlet 30 along the path indicated by the arrows 70.

Obviously many other specific cooling jacket arrangements may be made for causing desired flow of the cooling liquid through the jacket space of the converter.

As previously mentioned, the usual hydraulic working liquid is some form of oil or fluid which at normal temperatures is more viscous than water and in order to reduce the losses occasioned by high viscosity of the working liquid, it is generally desirable to operate the converter at relatively high temperature in order to reduce the viscosity of the working liquid, the normal desirable operating temperature of the working liquid usually being higher than the normally desired operating temperature of the engine cooling liquid which in nearly all instances manna" isswater, The presentinvention-enables-the desired -re1ative temperatures to be employed while at the same time obtaining a relatively high rate of heat flow through the convertereasing; Onithe one; handthere is within'athe converten a-. body of; working; liquid, operating; athigh temperatureiandahigh velocity; soithana high rate of. heat transfer! fromthe: liquid 1 to the casing isobtained-' even liquid. Consequently, the amount of .heatabsorption bythe cooling water necessary; to effectively cool the, converter canibe. obtained-with relatively-low velocity fiow of:.the coolingwater through the jacket, sopthat effective cooling tcan be-.=obtained; without material pressure drop and consequent absorption of powerfori circulating; the cooling liquid through the-*converter'jacket.

The. series fiowarrangement is particularly advantageous twheretheioperating conditionsv are suchv that the converter is under moreor lessconstant and substantial load. With such, an arrangementthe converter receives cooling water which is pre-heated by first passing :through. the engine jackets so that the coolingof'theconverter is, carriedloutat arelatively high level of cooling, water temperature; With constant load operation, even though the load'be; relatively heavy,;the amount'of heatrequired toibe absorbed' from the converter is still sufiiciently small so-that it can be satisfactorily absorbedin a series system.

Sotfar astthe jacketingarrangements shown in Figs. 3a and 5 are concerned, eithermay= be used, and it will be evident-that'manychanges in the design and arrangements of thetparts maybe made without departing from. the:' invention, which is to be considered as:embracing all formsof apparatus. falling within the scope of the appended claims;

What is claimed 1. The combination, withan engine having a liquid cooling system including an engine cooling jacket space provided with a thermostatic valve for controlling the flow of cooling liquid fromlthegoutlet thereof, a pump for circulating cooling liquid. andv a cooler, of ahydrodynamic torque converter driven by; the: engine" and comprising a housing structurehaving a walldefinin'g'the outer portion of. a. workingchamber inwhicha working, liquid is circulated. in-a1 closed path of flow in contact with said wall, a jacket around 'saidw'all andsp'acedjtherefro'm to provide a jacket space for'fl'ow of cooling liquid over said wall, said space having an inlet and an outlet, and connections arrangedi'toprovideforseriesfiow of coolingu-liquid-from the cooler through. the-engine jacket space and the converter jacket spaceback 'to'said cooler in the order named under the control of said thermostat.

2; Structure asdefinedimclaimvl in Wh'ichJth'e. jacket spacearound said wallrcontainsa plurality of bafiies pro vidi=ng-botlr.. an elongated-path of. flowthrough the eon! verterjacketpspace and extended-heat transfersurface for transmitting to, the cooling: liquid the'heat' conducted through. saidwall.v

RefereneessCited imthefiletof this patent- UNITED STATES PATENTS".

998,876 Daimler Iuly25, 1911 1,559,301 Barnard Oct. 27,1925? 1,688,968 Huwiler Oct. 23, 1928: 1,840,876: Rayburn Jan. 12, 1932 1 ,9'00,=1 18 Lysholm Mar; 7, .1933 1,915,547 Northet a1; June 27, 19331 2,164,173 Durrell et a1. June 27,1939" 2,175,448. Schlagintweit Oct; 10, 1939 2,310,269: Waeber Feb. 9, 1943 2,598,367. Fiser May 27, 1952 

